5 reasons wheel engraving door panels or any large glass is nuts.
ONE: Stationary glass lathes require the glass to move when cutting designs.
TWO THREE and FOUR: Plus glass weighs about the same as granite per cubic foot which means not only does a large glass engraving have to be setup to swing freely over the wheel in all directions, it also must have a substantial counter weight to make it at all manageable and it can NOT interfere with the free movement.
FIVE: One mistake either- cutting the design or polishing the cuts or hand grinding or trimming the panel afterward and kiss what could easily be a week's work goodbye. Or just call it "practice" if you've already lost your marbles.
So- got an old roller barn door rail and wheel carriage and bolted it to a 14' 2x10 nailed to 2 posts in the Barn studio in Maine in the early '80s. From a Volvo car wreck, took a steering column that had a universal joint on each end of it and connected 1 end to the overhead wheels and the other end to an eye bolt in the center of an oak balance beam. The universal joints gave decent freedom of movement, but dampened a pendulum effect. On one end of the beam, glass panels were hung and the other end took weights added on to offset the glass.